Gelatin is a widely used food ingredient and has been used to modify the texture of food product such as desserts, ice cream and frozen confections. An example of such a disclosure is contained in U.S. Pat. No. 4,297,379 to Topalian et al., entitled, "Frozen Aerated Ready-To-Eat Gelatin Composition".
When gelatin is used in the preparation of a ready-to-eat food product (as opposed to a powdered, gelatin-containing mix which the consumer dissolves in water) one of the initial steps in the process has been to dissolve the gelatin in hot water and then to quickly utilize the solution in the preparation of a product, typically a refrigerated or frozen product. As it is known to be undesirable to hold gelatin solutions for a prolonged period of time, especially in a low pH environment, delays in using the gelatin solution have been minimized.
The time limitation for the holding of gelatin solutions results from a combination of two factors -- namely, the susceptibility of the gelatin solution to microbial growth and hydrolysis of the dissolved gelatin, especially at acidic conditions and elevated temperatures. Reducing the temperature of the solution in order to slow down microbial growth and/or hydrolysis is not possible as the solution will begin to gel.
Another problem encountered in the formation and use of gelatin solutions is the fact that gelatin hydrates relatively slowly. Accordingly, it is common practice to employ finely ground gelatin (e.g., at least 90% by weight through a 40 U.S. mesh screen and less than 40% by weight through a 100 U.S. mesh screen) and hot water so that the gelatin may be dissolved in a reasonable period of time. The manner in which the gelatin is added to the hot water is, however, limited by the fact that gelatin particles tend to clump together as they are introduced into an aqueous medium. This problem is usually solved by preblending the gelatin particles with another particulate material, typically sugar and/or food acid. Such a preblending step is costly in terms of both time and equipment requirements and would desirably be eliminated.
The inability to maintain an acid-containing gelatin solution for an extended period of time can hamper the continuous production of ready-to-eat (e.g., refrigerated or frozen) gelatin-containing food products. To date, in order to supply an aqueous gelatin solution to continuous heat exchange (e.g., pastuerizer, freezer, etc.) and/or filling equipment, it has been necessary to frequently (e.g., every four hours) prepare fresh gelatin solutions. It would be highly desirable to develop a system for supplying concentrated gelatin solutions to a continuous process without the need for frequent batch preparations of solution.
It is known, as exemplified by U.S. Pat. No. 2,819,970 to Steigman, that cold-water soluble gelatin can be produced by drying an aqueous gelatin solution in a manner which preserves the gelatin in a molecularly-dispersed, amorphous form rather than the usual crystalline form. Cold-water soluble gelatin is, however, relatively expensive, is quite moisture-sensitive and, as noted in U.S. Pat. No. 3,930,052 to De Brou et al., is difficult to disperse in cold water. Consequently, cold-water soluble gelatin has not been used in the commerical production of ready-to-eat, gelatin-contining food products. The use of cold-water soluble gelatin is not within the scope of the present invention as the gelatin solution would tend to set up (i.e., gel) during extended holding periods.